Use ScrollTrigger Progress in Tween

[scottyak]

I'd like to use the progress from a ScrollTrigger instance to update the value for a tween (in this case, pushing a title element down within a pinned element). I tried the below, I can get the progress un on Update, but I'm not sure how to apply it to the tween:

 

let el = document.querySelector(".section-title");

 

gsap.to(el, {

y: () => self.progress * (window.innerHeight * 3),

ease: 'none',

scrollTrigger: {

  trigger: ".col-left",

  start: "top top",

  end: "bottom bottom",

  onUpdate: (self) => console.log(self.progress),

  scrub: true,

}

});

[GSAP Helper]

Without a minimal demo, it's very difficult to troubleshoot; the issue could be caused by CSS, markup, a third party library, a 3rd party script, etc. Would you please provide a very simple CodePen or Stackblitz that illustrates the issue? 

 

Please don't include your whole project. Just some colored <div> elements and the GSAP code is best. See if you can recreate the issue with as few dependencies as possible. Start minimal and then incrementally add code bit by bit until it breaks. Usually people solve their own issues during this process! If not, at least we have a reduced test case which greatly increases your chances of getting a relevant answer.

 

See the Pen aYYOdN by GreenSock (@GreenSock) on CodePen

that loads all the plugins. Just click "fork" at the bottom right and make your minimal demo: 

 

Using a framework/library like React, Vue, Next, etc.? 

CodePen isn't always ideal for these tools, so here are some Stackblitz starter templates that you can fork and import the gsap-trial NPM package for using any of the bonus plugins: 

• React (please read this article!)
• Next
• Svelte
• Sveltekit
• Vue
• Nuxt

 

Please share the StackBlitz link directly to the file in question (where you've put the GSAP code) so we don't need to hunt through all the files. 

 

Once we see an isolated demo, we'll do our best to jump in and help with your GSAP-specific questions. ✅

[Cassie]

I've squinted at this a bit and I'm very confused as to *why* you're needing to do this

A tween hooked up to a scrubbed ScrollTrigger is already inherently hooking the value up to the progress.

 

This is going to tween from the original position, to window.innerHeight over the time it takes the person to scroll between the start and end point. i.e. over the progress of the scrolltrigger.

let el = document.querySelector(".section-title");
 
gsap.to(el, {
y: () => window.innerHeight * 3,
ease: 'none',
scrollTrigger: {
  trigger: ".col-left",
  start: "top top",
  end: "bottom bottom",
  onUpdate: (self) => console.log(self.progress),
  scrub: true,
}
});

 

[Cassie]

Another valid pattern would be using the onUpdate callback to update an animation. So something like this

 

let tween = gsap.to(".something-else", {
  rotation: 360,
  paused: true,
})

gsap.to(el, {
y: () => window.innerHeight * 3,
ease: 'none',
scrollTrigger: {
  trigger: ".col-left",
  start: "top top",
  end: "bottom bottom",
  onUpdate: (self) => {
    tween.progress(self.progress)
    
    // or maybe?
    gsap.set(".another-thing", {
     y: self.progress * 2
    })
  },
  scrub: true,
}
});

 

Maybe these patterns help you? As the helper said, a demo would be great though.

[scottyak]

See the Pen NWmjpod by scottyak (@scottyak) on CodePen

 

Just trying to have the section title stay pinned to the top of the element while the section is in view. Is there a better way to do this?

[Rodrigo]

Hi,

 

As well as Cassie I'm a bit confused about your approach. We have a codepen collection filled with ScrollTrigger demos that could be helpful:

https://codepen.io/collection/AEbkkJ?cursor=eyJwYWdlIjoxMn0=

 

Also, if I'm understanding correctly what you're trying to do, maybe some of these demos could help:

See the Pen NWMZrbj by GreenSock (@GreenSock) on CodePen

 

See the Pen eYQYxJW by GreenSock (@GreenSock) on CodePen

 

See the Pen wvYVjvb by GreenSock (@GreenSock) on CodePen

 

Happy Tweening!

[Cassie]

Ah ok, that's great, thanks for the explanation. Like this?

See the Pen NWmjjNv by GreenSock (@GreenSock) on CodePen

[scottyak]

Yes, that's perfect, thanks! I figured that would add pin spacing under the element and make the section longer than I wanted, but I guess not.

 

Thanks again!